Charge pumps, or voltage multipliers, are commonly used in integrated circuit (IC) applications to boost a main supply voltage to a higher voltage. In some applications, the higher voltage must be generated internally within the IC to avoid the use of an externally-applied voltage. Post-regulated charge pumps, which sense the output voltage of the charge pump and utilize a control loop to regulate the output voltage, offer voltage accuracy at the expense of increased complexity and power consumption. However, not all applications require the voltage accuracy provided by post-regulation and, therefore, added overhead associated with post-regulation.
Applications that do not require high accuracy often utilize unregulated charge pumps, which result in a reduced complexity and smaller area requirement. However, output voltages that stray outside the application voltage limits, even in applications not requiring high accuracy, may result in stress on a load device and/or other undesirable effects.